A spider's silk is as strong as the Kevlar woven into bulletproof vests and more elastic than nylon, making it tougher than any material made by human hands. Generations of scientists have tried to mass produce it and failed.
Amanda Brooks, though, may be close.
Brooks, an assistant professor at North Dakota State University, has developed an intriguing device she thinks will be a big advance in the effort to spin synthetic spider silk and recreate the strong, stretchy fibers.
Given the advances in modern technology — and the fact that Spider-Man is everywhere these days — it might seem surprising to learn that while science understands the powers of spider silk, it's been unable to replicate it consistently.
Researchers have learned to create synthetic fibers by unraveling spider DNA to understand the proteins that are the building blocks of spider silk, but they've been thwarted trying to collect spider silk in large quantities. While silkworms can be farmed to collect silk fibers, spiders eat each other. So, mass producing the silk is a challenge.
Spinning the synthetic material into fibers has proven very difficult, although researchers have tried many techniques over the years.
Idea spun over dinner
Brooks came up with a new approach during a dinner conversation with her engineer husband about microfluidics, the science of precise control and manipulation of liquids. The 3D-printed device she built uses small channels to produce very consistent fibers.
Spiders spin a half-dozen different kinds of fibers, she explained. "Most researchers care about one kind and that's the dragline silk. That's the one that if the spider falls from the ceiling, that's what they're using, that's their lifeline."
A single silk fiber is one-tenth to one one-hundredth the diameter of a single human hair, she noted.
"There's so many potential uses that there has been quite a bit of effort put into figuring out how to spin it," she said. "People have been able to do it, but the fibers that are being produced are typically inconsistent so there's a lot of variability in terms of the diameter and the mechanical properties."
Unraveling genetics of spider silk
Researchers across the country are trying to develop lightweight strong fabrics, flexible coatings for medical devices or adhesives.
There have been many attempts and failures to replicate the work of spiders over the years. Randy Lewis, a professor at Utah State University who has studied spiders for 30 years, unraveled the genetics of spider silk and has numerous patents on those discoveries.
Lewis says the NDSU research is a novel approach to making silk fibers.
"I'm not sure how far down the road to mass production this research is going to push the ball, just because to scale up to large quantities is probably going to certainly, I think, encounter some difficulty," said Lewis.
He said he thinks the challenge will be retaining the strength and flexibility that makes spider silk unique, but Brooks believes the device can be used to create commercial amounts of fiber, and in many different sizes targeted for different uses.
Replicating spiders not cheap
After years of research, Lewis said scientists are tantalizingly close to commercial production of a wide variety of materials.
"It's not just going to be a drug [or] a coating on one kind of thing. It's going to be a number of different kinds of materials used for a number of different applications. I think that's part of the reason why we see it as having a very high commercial potential," said Lewis.
Spider silk uses will always be limited by production costs, he said.
"I'm not sure that it'll ever be cost competitive in some markets because you know making nylon is cheap and making spider silk is never going to be cheap," said Lewis. "You're never going to be able to make it cheap enough to make a $5 T-shirt."
Brooks is focused on biomedical uses for the spider silk. For example, the fibers can be infused with antibiotics to make bandages or surgical sutures. She also believes tiny bubbles of spider silk can be used as a drug delivery system in the body.
"I think our device kind of paves the way for some new thought processes and new things that we could potentially do," said Brooks. "I think that this actually does kind of put us near the forefront of this field."